Process of making alcohols by use of ethyl sulphuric acid



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May 25, 1937. B. T. BROOKS 2,081,166

PROCESS oF MAKING ALcoHoLs BY USE oF ETHYL sULPHuRIc ACID Filed Dec. 23, 1935 .sc 20335:, c omo: N san @f ffl. ,0 v f2 2f TAN 164D TANK GA s #uur Q ru 7 .mar/u. uva COQLf-P- A ,a R s coLuMN owe .SuLFun/e Ac/D 007157' Re: lawn.. i GA: aunar T5 l l t @www rimmed` May 25,? 1937 PROCESS O MAKING ALCOHOLS BY USE F ETHYL SULPBUBIO ACID Benjamin 'i'. Brooks, ola Greenwich, com.,

assigner to Standard Alcohol Company V Application December 23, 1935, Serial No. 55,792

10 Claims (Cl. 2601-156) This invention relates to improvementsin the manufacture of alcohols, vparticularly ethyl,` isopropyl, secondary butyl, and tertiary butyl alcohols. Instead of the 'conventional acid solution,

such as sulphuric acid, the present invention utllizes mono-ethyl sulphate (ethyl sulphuric acid) or another suitable mono-alkyl sulphate, preferably in' sulphuric acid solution. The mono-ethyl sulphate is prepared from ethyl ethenformed as a by-product in the alcohol reaction. Better results are obtained through the elimination of the sidek reactions induced by sulphuric acid when used alone, and economies are effected.

' The formation of ethers in the process of making alcohols by sulphating olens and hydrolyzing the resulting productis a. disadvantage when maximum yields of alcohol are desired. An important object of the present invention is to utilizeethers so formed, especially ethyl ether, by converting it into mono-ethyl sulphate, which will -serve as an improved sulphating agent for oleflns, such as ethylene, propylene and the butylenes. Similarly, propyl and butyl ethers or the like may be utilized. Ethers. may of course `be obtained from any desired source, but for economyfethers formed in the processshould be used.

Another object of the invention is tocontrol the sulphation reaction and render it less drastic by semi-neutralizing sulphuric acid.' that is to say, using it in the form of the mono-alkyl sulphate, particularly mono-ethyl sulphate, `in accordance with the following general equationsrj Thus, in accordance with Equation I, one molecular proportion of ethyl ether requires two molecular proportions of sulphuric acid for the formation of. two molecules of mono-ethyl sulphate. In the improved process, represented by Equations l1 and III, a substantial economy of sulphuric acid is obtained by reacting upon the mono-ethyl sulphate vwith propylene, to form ethyl-isopropyl sulphate, which is then hydrolyzed to produce a. mixture of ethyl and isopropyl alcohols. A small proportion of a mixture of ethers may be formed which are returned to the cycle of operations, i. e., treated with sulphuric acid to form mono-alkyl sulphates which are in turn reacted with more propylene.

A further object of the invention is toy secure initially the beneficial effect of mono-alkyl sulphates; that is, without waiting forfthem to be formed in the sulphation of-the 4oleflns.

' In a preferred form of the process of the present invention, ethyl ether, or a mixture of ethers containing for example ethyl ether, ethyl isopropyl 5' ether and di-isopropyl ether, or `one or more of these ethers, is dissolved-in an excess ofsulphuric acid having a concentration within the range of about 88 per cent to 98 per cent H2804, and the sulphuric acid solution is then heated to 100-A 10 120 C. for about one hour or until the formation of alkyl acid sulphates is substantially complete. The alkyl acid sulphate may advantageously be present in the amount of 10 to 20% by volume of the sulphuric acid.` Higher concen- 15 trations, up to 100% alkyl acid sulphate, are suitable, but usually less convenient to prepare. The acid reaction product containing alkyl acid sulphates and sulphuric acid is then cooled and used for reacting with an olefin, especially propylene or a gas mixture containing propylene. 'I 'he'nal reaction product thus obtained ishydrolyzed and. distilled to give ethyl and isopropyl alcohols.

'I'his `combination of operations has advantages over treating propylene, or gas containing propylene, with sulphuric acid alone. When treating propylene with sulphuric acid, the reaction isincreasingly. rapid as the concentration of the acidis increased within the range 85-98% H2504 and is very diillcult to control, as by cooling the acid mixture, when acid concentrations greater than about 91 per cent H2SO4 are employed. Monoethyl sulphate, or sulphuric acid containing substantial proportions of mono-ethyl sulphate is milder in its reaction with propylene and the 35 process is more easily controlled.y Side reactions such as polymer and tar formation are greatly reduced. Moreover, the mono-alkyl sulphate appears to have an accelerating effect on the olefin absorption. This can be observed inthe usual process, for when the acid begins to be alkylated, the absorption rate rises, up to the point where the acid approaches exhaustion.

Another advantage of the present invention is in thehigher yield of alcohols obtained by the use of a given quantity of acid. Thus, in the absorption of propylene by sulphuric acid, the proportion of` di-isopropyl sulphate which is formed is greatly aifected by thepercentage of water in the sulphuric acid used.v Thus an acid solution containing 85-88% sulphuric acid will form less di-lsopropyl sulphate than a solution oi' 9193% sulphuric acid. Side reactions, such as polymerization and tar formation, and the difculties of control by cooling, render it dilllcult or practically impossible to build up very high concentrations of di-isopropyl sulphate with acid containing less than 9 per cent water. However, an acid solution containing 98 per cent Sulphuric acid can be used in converting ethyl ether to mono-ethyl sulphate and the resulting mono-ethyl sulphate can then be employed to react smoothly with propylene to form large proportions of ethyl-isopropyl sulphate, with a corresponding increase in acid eiciency or higher yield of alcohols per given quantity of acid.

Further objects and advantages of the invention will be apparent from the following description, read in connection with the accompanying drawing, in which the single gure is a diagrammatic side elevation of suitable equip ment for carrying out the process, as applied to the manufacture of isopropyl alcohol. Ethylene or gas containing ethylene is passed through a pipe into the olefin absorbing tower 2. Sulphuric acid is passed into absorber 2 from a source of supply 3 and residual gas escapes from the absorber through the exit pipe ii. The rei taining the pressure in the absorber 2, are used.

Hydrolyzing tank 6 is supplied with water through a pipe 1. 'Ihe water supplied to hy-L1 drolyzer 6 is preferably preheated to maintain the temperature ofthe hydrolyzer at about 80 C. The diluted and hydrolyzed or partially hydrolyzed reaction mixture is removed from hydrolyzer E by pipe l to a distilling column 8,

where the hydrolysis is completed and the volatile products, ethyl alcohol and ethyl ether, are removed as vapors through a pipe Si and conducted to a condenser l0. The alcohol and ether vapors may be scrubbed by hot alkali solution in a. scrubber 9a to remove sulphur dioxide before passing to condenser lll. Steam is introduced into column 8 by a steam inlet pipe and dilute sulphuricacid is removed through a pipe l2.

f The mixture of alcohol and ether condensed in condenser ill is passed continuously by a pipe I3 to a column still I6, or the like, for separating the ether and alcohol. A steam heating coil l5 is located near the bottom of column I6. Alcohol is taken from a plate near the top of the column through a cooler I6, and the ether is taken as vapor through a pipe to a condenser I8.

Ethyl ether is passed from condenser I8 by a pipe I9 to an absorbing tower 20 where it meets concentrated Sulphuric acid which is passed into the tower from a source of supply 2|. The solution of ether in Sulphuric acid is passed from tower 23 by a pipe 22 to collecting tanks 23 and 26 which are heated by suitable means, as by steam coils, so regulated as to maintain a tem perature of about 10D-110 C.

The acid reaction product is removed from tanks 23 and 24 by a pipe 25 to a cooler or heat exchanger 2G where it is cooled to about 20\ C. The mono-ethyl sulphate then passes into the top of a reaction tower 2l' where it meets an as cending stream of gaseous propylene or gas containing propylene. 'Ihe propylene enters the reaction tower by a pipe 28 and the residual gases are removed through a pipe 29. The 'acid reaction product containing ethyl-isopropyl sulphate is passed from the bottom of reaction tower It will be understood that 21 through a line 21a to a hydrolyzing tank 30 and after hydrolysis the solution is distilled, as for example in a distilling column such as shown diagrammatically at 3|.

Dilute sulphuric acid is removed by a pipe 32 and steam is passed into column 3| by a pipe 33. Thev volatile products, mainly ethyl and isopropyl alcohols and small proportions of ethy ethers formed from the mixed ethyl-isopropyl sulphate may optionally be returned to the absorbing tower 20 through line 38, or otherwise disposed of.

The foregoing description has dealt mainly with the production of'isopropyl alcohol. It will be understood, however, that the principles of the invention are also applicable to the butylenes. Thus, the four-carbon atomfraction obtained from petroleum' refinery gases may be reacted with mono-ethyl sulphate. It is usually not desirable to attempt the separation of the ethyl and isopropyl alcohols, as this is diicult and for many purposes the mixture serves as well as or better than the pure alcohols. The butyl alcohols, however, may be readily separated from the reaction mixture by fractional distillation. When preparing butyl alcohols, the acid reaction product should not only be cooled but the ethyl sulphuric acid should be diluted with water to bring the acid concentration downto about -90% sulphuric acid before treating the butylene.

Where butylenes are referred to herein, the term is intended to mean butene-l, butene-2, or isobutylene, where the context so permits. The temperature of treatment should be about 20 C.

Sulphuric acid is usually to be preferred, but phosphoric acid and other suitable poly-basic mineral acids may be used. The ether absorption in the acid will be conducted so as to leave a portion of the acid hydrogen available for olen reaction.

The foregoing description is merely illustrative and various changes may be made within the scope of the appended claims in which it is my intention to claim all novelty inherent in the invention as broadly as the prior art permits.

I claim:

1. Process of making an alcohol, comprising reacting an aliphatic ether with a poly-basic mineral acid to make an alkyl compound containing residual acid hydrogen capable of reacting with oleins, reacting an olefin with the alkyl compound and hydrolyzing the resulting compound to produce an alcohol.

2. Process of making alcohol, comprising reacting an aliphatic ether with Sulphuric acid to make a mono-alkyl sulphate, treating an olen with the mono-alkyl sulphate and hydrolyzing the resulting compound to form an alcohol.

3. Process of making isopropyl alcohol, comprising reacting' ethyl ether with Sulphuric acid,

bringing the resulting mono-ethyl sulphate into be converted into a butyl alcohol, comprising reacting an aliphatic ether with sulphuric acid to form a mono-alkyl sulphate, and treating a butylene with the mono-alkyl sulphate.

6. Process according to claim 5 in which the ether is obtained as a by-product in the manufacture of ethyl or isopropyl alcohol.

'7. Process according to claim 5 in which the ether is ethyl ether obtained as a by-product in the manufacture of ethyl alcohol.

8. Process of making alcohols from hydrocarbon gases containing olens, comprising passing the gases through an initial acid treatment stage in which the olens are sulphated, with the production of ethers as by-products, -reacting the ethers with sulphuric acid to form mono-alkyl sulphate, treating an olen with the mono-alkyl sulphate, and hydrolyzing the resulting di-alkyl sulphate.

9. Process according to claim 8 in which the ether obtained is predominantly ethyl ether and the olens reacted with the mono-alkyl sulphate are butylenes. 4

10. A cyclic process for the manufacture of a1- cohols from olefin-containing gases, comprising absorbing the olen in sulphuric acid to make a di-alkyl sulphate, hydrolyzing and distilling the di-alkyl sulphate to form alcohol and ether as a by-product, withdrawing the alcohol, absorbing the ether in sulphuric acid and converting it into mono-alkyl sulphate, reacting the mono-alkyl sulphate with an olefin to produce a di-alkyl sulphate, hydrolyzing the di-alkyl sulphate with the production of alcohol and a minor proportion of ether, withdrawing the alcohol, and returning the ether to thev ether absorbing step.

BENJAMIN T. BROOKS. 

